1. Field of the Invention
This application is a 371 of PCT/EP05/053027, filed Jun. 28, 2005, and claims priority to French Patent Application No. 04.07158, filed Jun. 29, 2004.
The subject of the invention is a container for the thermal conditioning of a fluid under pressure, its use, a chemical reactor, a polymerization process using it and a method of manufacturing the container and the reactor.
2. Description of Related Art
When it is necessary to carry out heat exchange in a container intended to contain a fluid under pressure, one is generally confronted with the problem of controlling the heat exchange (thermal conditioning of the fluid), namely to remove the heat generated or to supply the heat needed. In particular in exothermic or endothermic reactions, one is faced with the problem of removing the heat generated by the reaction or alternatively supplying the heat needed for it.
Many containers intended to contain fluids under pressure have already been described, in particular those in which a double-walled jacket in which the heat-transfer fluid for controlling the heat exchange circulates, is fixed to the outer face of the outer wall of the container. In this particular case, the heat flux must pass through the thickness of the wall, which results in low heat exchange coefficients for heat exchange between the fluid under pressure and the heat-transfer fluid, leading in the particular case of a polymerization reaction to an increase in the polymerization time and a loss of efficiency of the plant.
Other containers intended to contain fluids under pressure in which the double-walled jacket is fixed to the inner face of the outer wall of the container have also been described.
Thus, document EP 0 012 410 B1 describes a container for carrying out exothermic and endothermic reactions, in particular the polymerization of vinyl chloride by controlling the heat exchange by means of a heat-transfer fluid circulating in a double-walled jacket fixed to the inner face of the outer wall of the apparatus. The double-walled jacket is produced by welding, to the internal face of the wall of the container, a semi-tubular coil consisting of half-tubes in the form of semicircular tubes so that they form a winding with touching turns. This type of container is characterized by a better heat exchange coefficient than those exhibited by the prior containers with a double-walled jacket fixed to the outer wall of the container, but it is still low. It is also complicated to produce, resulting in very high construction costs. Finally, because the half-tubes form, between them, on the inside of the container a very sharp angle (a discontinuity), this type of container has a major drawback, as the container shown diagrammatically in Patent Application FR 2746488 also has, in particular when it is used for a polymerization, especially for the polymerization of vinyl chloride, namely the fact that the polymer formed is disadvantageously deposited in the regions between the half-tubes on the inside of the container. This means that the polymerization cycle has to be interrupted more often in order to clean the reactor. The productivity of such a process is greatly affected thereby.